Not really - without God (even if you only want to accept it as a theoretical term used by the less intelligent, which I am sure you do) there would be no discussion on the topic
Do not confuse necessity with causality. A discussion about God could not occur without the idea of God, the original poster, and the other participants in the discussion. If any of these are lacking, then a discussion on God there is not.
Causality refers to something not only logically necessary but necessarily chronologically antecedent. While God as a concept may be older than any of the humans involved in the discussion, God is only logically necessary to the discussion precisely at the time the discussion takes place. However, preceding the discussion or even the decision to begin it, there must be an originator, who may conceive independently of the same God and then decide to discuss it with others.
I am one who believes that words are defined by consensus, so God, like any word, is nothing in and of itself. Therefore, and again as with other words, God means to me what it means to others; and so depending on who I am discussing God with, I may or may not be a theist.